Rail flaw detector mechanism



acme, 1934- L. J. DE LANTY ET AL RAIL FLAW DETE GTOR MECHANISM Filed Jan. 25, 1955 1. Walter M. Parr? INVENTORS Loren J. DeLan ATTORNEY Patented a. it, rest UNITE STATES A-TENT' GFFICE RAIL FLAW DETECTOR 3.

- of New York Application January 25,1933, Serial No. 653,446

14L Claims.

This invention relates to rail flaw detector mechanism of the type employed in the Sperry rail flaw detector car. In said car a current brush carriage is provided for sending current 5 through the rail to establish an electro-magnetic field surrounding the same and a detector carriage supporting a detector unit is operated over the rail, said detector unit comprising a plurality of opposed coils for cutting the lines of force surrounding the rail. This operation is now well known and results in the opposed coils cutting the same number of lines of force when no flaw is present so that no E. M. F. is generated. but when a flaw is encountered one coil on entering or leaving the region of fiaw cuts a difierent number of lines of force from the other coil to enerate a difierential E. M. F. which is then amplified to such an extent that the output is capable of operating an indicator such as a re- 2 corder.

This invention has for its principal object improvements in the detector carriage and the detector or search unit supported thereby. These improvements result in more accurate operation 5 of the detector mechanism with a reduction of false indications, that is, indications due to surface defects and other causes which are not internal fissures.

In the accompanying drawing,

Fig. 1 is a side elevation of a portion of a Sperry rail flaw detector car showing our invention applied thereto.

Fig. 2 is an enlarged view of a portion of the mechanism shown in Fig. 1.

Fig. 3 is a section taken substantially on the line 3-3 of Fig. 2.

Fig. 4 is a vertical section taken substantially on the line H. of Fig. 2.

Figs. 5 and 6 are views similar to Fig. 4. of the 40 old construction heretofore employed and which show the advantages of the Fig. 4 construction.

Fig. 7 is an enlarged View partly sectioned showing one of the universal joints between a search unit and the detector carriage of Fig. 2.

Referring to the drawing, a portion of the Sperry detector car is shown as comprising the car body 10 from which is suspended a current brush carriage 11 by means such as universally mounted fluid pressure cylinders 12 from which 50 project pistons 13 connected to the current brush carriage whereby said carriage may be lowered when fluid pressure is admitted to the cylinders. When it is desired to raise the current brush carriage the fluid pressure is out 55 on and the carriage is raised by means such as cables 15 and attracting springs not shown. The current brush carriage comprises flanged wheels 16 adapted to engage the rail R; so that as the car moves along the track the said cur' rent brush carriage also moves along the track 30 and current is at the same time sent into and taken out of the rail by means of sets of brushes l7 and 18 supplied with current from a generator, not shown, within the car body.

The current thus admitted to the rail establishes an electromagnetic field surrounding the rail, said field being uniform except where there occur flaws which change the direction of flow of current and thus distort the field. Such deviation of the flow of current due to flaws are de- 7 tected by a detector or search unit 19 comprising a pair of opposed induction coils contained within cylinders 20, said cylinders being adapted to ride along the rail. This type of detector unit is disclosed in the patent to Harcourt C. Drake, No. 75 1,907,755 issued May 9, 1933. As the detector unit operates along the rail the cylinders or rollers 20 maintain the coils a fixed distance above the rail so that as long as the electro-magnetic field is uniform each coil cuts an equal number of lines of force and no differential E. M. F. is generated. But when a flaw is encountered the coils on entering the region of said flaw out different numbers of lines of force and generate a differential E. M. F. which may then be amplified to cause operation of an indicator such as a recorder.

The search unit 19 is mounted on a detector carriage which is in .tum mounted on the current brush carriage 11. The detector carriage 25 is provided -with wheels 26, 26' for operating on the track and said carriage 25 is suspended from the current brush carriage 11 by means such as bolts 2'7 pivotally connected to the carriage 25 by longitudinally positioned pivots 28 so that the carriage may pivot transversely to adjust itself to the irregularities in the rail surface. The bolt 27 may operate vertically within a bearing 30 in the carriage 11 so that the detector carriage 25 may adjust itself vertically with respect to the carriage 11 100 as the car runs along the rail.

Any lateral swaying of the current brush carriage 11 would tend to carry the entire detector carriage 25 laterally unless the pivot 28 were closely adjacent the rail surface. As shown, 105 the pivot is as close to the rail surface as the construction of this joint will permit so that any lateral swaying of the current brush carriage 11 is really around the pivot 28 or substantially at the rail surface so that the d no tector carriage 25 is not carried laterally by such swaying of the current brush carriage. If the pivot 28 were higher, the pivot would be carried laterally as the current brush carriage swung laterally and thus the search unit would be swung laterally and this would cause the coils to cut a different number of lines of force and give an indication as of a flaw. In other words, false indications due to lateral movements of the current brush carriage 11 are prevented by pivotally supporting the detector carriage 25 at a point as closely adjacent the rail surface as the construction of this joint will permit.

Just as in the case described above where the lateral swinging of the current brush carriage tends to swing the detector carriage 25 with it unless the pivotal connection between them is closely adjacent the rail surface, so lateral movements of the detector carriage 25 tend to carry the search unit 19 with it-unless the connection betweenthe search unit and the detector carriage 25 is also as closely adjacent the rail surface as the construction of the connection will permit. For this purpose, the search unit 19 is mounted on the detector carriage 25 by means such as bolts 40 extending through the carriage 25 and through the frame 41 in which the rollers 20 are mounted, the said bolts 40 being connected to the carriage 25 by a universal joint as close to the rail surface as the construction of this joint will permit. This joint is formed by the rod 41 being threaded into a pivot 42 carried by a bracket 43, the said bracket being in turn pivoted at 45 in a bracket 46 fixed to the frame of carriage 25. It will be seen that this universal joint is so positioned that it allows only enough clearance between it and the rail surface to permit the moving elements to operate freely. The upper end of bolt 40 extends freely through the frame of carriage 25 so that the unit 19 is free to pitch or roll without hindrance. The frame 41 which carries the rollers 20 may be held in firm engagement with the rail by means such as springs 47 interposed between the under side of the frame of carriage 25 and the frame 41. By this construction, any lateral movements of carriage 25 will not result in lateral movement of unit 19 but will only result in the carriage 25 pivoting around the carriage 19 at the universal joint which is practically at the rail surface, so that there is substantially no lateral movement of said joint.

In older forms of detector carriage mountings the detector carriage 25 was held firmly on the rail by means such as conical springs 50 interposed between the undersurface of the frame of carriage l1 and a seat 51 provided in the upper end of the detector carriage 25 through which the bolts 2'7 extended downwardly to the pivots 28. Since the detector carriage 25 operated along the rail and was free to adjust itself to the varying contour of the rail surface it was found that there were times, particularly in traveling around curves, when one side of the spring 50 would be under greater compression thanthe other side, as shown in Fig. 6. This difference in compression between the two sides of the spring set up a tendency of the spring to equalize itself by imparting lateral movement to the detector carriage 25 until the carriage was in centralized position. This tendency at times caused lateral movement of the carriage 25 with corresponding lateral movement of the detector coils which resulted in a false indication of flaw. We have obviated this objection by providing an extra flange or shoulder 53 on the bolt 27 against which the spring may press instead of having the lower end of said spring in direct engagement with the detector carriage 25. As a result of this construction lateral or pivotal movements of the detector carriage 25 will not cause any differential compression of the sides of the spring which will at all times remain in centralized, undistorted position.

Heretofore, the detector carriage has been mounted upon sets of wheels at the front and rear, each set comprising two laterally spaced wheels 26 on which the detector carriage rode along the rails. We have found that the carriage is better able to maintain parallelism with the rail surface at all times in spite of irregularities in the rail surface if three-position instead of four-position suspension is employed. Thus, instead of using pairs of laterally spaced wheels at the front and rear we may employ such sets only at the front or rear to give support at two lateral positions, and single wheels 26 at the other end to give support at one central position. This three-position support gives the same stability to the carriage as heretofore, while permitting a better adjustment of the position of-the carriage in response to irregularities in the rail surface.

In accordance with the provisions of the patent statutes, we have herein described the principle and operation of our invention, togetherwith the apparatus which we now consider to represent the best embodiment thereof, but we desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering'with the more general results outlined, and the invention extends to such use.

Having described our invention, what we claim and desire to secure by Letters Patent is:

1. In a flaw detector mechanism for rails, a detector carriage adapted to engage the rail surface, a support for said carriage, a search unit adapted to engage the rail, and means whereby said unit is mounted on said carriage, said means including a pivotal connection closely adjacent the rail surface.

2. In a flaw detector mechanism for rails, a

detector carriage adapted to engage the rail surface, a support for said carriage, a search unit adapted to engage the rail, and means whereby said unit is mounted on said carriage, said means including a pivotal connection as closely adjacent the rail surface as the mechanical construction of the connection will permit.

3. In a flaw detector mechanism for rails, a detector carriage adaptedto engage the rail surface, a support for said carriage, a search unit adapted to engage the rail, and means whereby said unit is mounted on said carriage, said means including a universal joint closely adjacent the rail surface.

4. In aflaw detector mechanism for rails, a detector carriage adapted to engage the rail surface, a support for said carriage, a search unit adapted to engage the rail, and means whereby said unit is mounted on said carriage, said means including a universal joint as closely adjacent the rail surface as the mechanical construction of the connection will permit.

5. In a flaw detector mechanism for rails, a current brush carriage, a detector carriage, said carriages being adapted to engage the rail, means whereby said detector carriage is mounted on said current-brush carriage, said means including a pivotal connection closely adjacent 'the rail surface, a search unit adapted to engage the rail, and means whereby said unit is mounted on said detector carriage, said last-named means including a pivotal connection closely adjacent the rail surface.

6. In a flaw detector mechanism for rails, a current brush carriage, a detector carriage, said carriages being adapted to engage the rail, means whereby said detector carriage is mounted on said current-brush carriage, said means including a pivotal connection as closely adjacent the rail surface as the mechanical construction of the connection will permit, a search unit adapted to engage the rail, and means including a universal connection whereby said unit is mounted on said detector carriage, said connection being as near the rail surface as the mechanical construction thereof will permit.

7. In a flaw detector mechanism for rails, a current brush carriage, a detector carriage, said carriages being adapted to engage therail, means including a pivotal connection permitting movement about an axis longitudinal of the rail whereby said detector carriage is mounted on said current brush carriage, and resilient means interposed between said carriages and indirectly connected to said detector carriage for maintaining said detector carriage in firm engagement with the rail.

8. In a flaw detector mechanism for rails, a current brush carriage, a detector carriage, said carriages being adapted to engage the rail, and means including a pivotal connection permitting movement about an axis longitudinal of the rail whereby said detector carriage is mounted on said current brush carriage, said means including a link connected to said detector carriage and resilient means interposed between said link and said current brush carriage for maintaining said detector carriage in firm engagement with the rail.

9. In a flaw detector mechanism for rails, a current brush carriage, a detector carriage, said carriages being adapted to engage the rail, and means including a pivotal connection permitting movement about an axis longitudinal of the rail whereby said detector carriage is mounted on whereby said detector carriage is mounted on said current brush carriage, said means including a link pivotally connected to said detector carriage so as'to beindependent of the pivotal movements of said carriage, a flange on said link, and resilient means interposed between said flange and said current brush carriage for maintaining said detector carriage in firm engagement with the rail.

11. In a flaw detector mechanism for rails, a detector carriage adapted to engage the rail, a search unit mounted on said carriage, and means whereby said carriage is supported on said rail by a three-position support.

12. In a flaw detector mechanism for rails, a detector carriage adapted to engage the rail, a search unit mounted on said carriage, and means whereby said carriage is supported on said rail by a three-position support, said last-named means comprising means at one end of the carriage for engaging the rail at a plurality of laterally-spaced positions, and means at. the other end for engaging the rail at a single position.

13. In a flaw detector mechanism for rails, a detector carriage adapted to engage the rail, a search unit mounted on said carriage, and means whereby said carriage is supported on said rail by a three-position support, said last-named means comprising means at one end of the carriage for engaging the rail at a plurality of laterally-spaced positions, and means at the other end for engaging the rail at a substan- 1 tially central position on the rail.

14. In a flaw detector mechanism for rails, a detector carriage adapted to engage the rail, a search unit mounted on said carriage, and means whereby said carriage is supported on said rail by a three-position support, said last-named means comprising double, laterally-spaced wheels at one end of the carriage, and single wheels at the other end.

LOREN J. DE LANTY. WALTER M. PERRY. 

